Swimming fins or flippers



Sept. 25, 1962 L. FERRARO ET AL 3,055,025

SWIMMING FINS OR FLIPPERS Filed Feb. 25, 1960 s sheets-sheet 1 IN VENTORS' Sept. 25, 1962 L. FERRARO ET AL SWIMMING FINS OR FLIPPERS 3 Sheets-Sheet 2 Filed Feb. 25, 1960 FIG. 4

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Sept. 25, 1962 FERRARO ET AL SWIMMING FINS OR FLIPPERS 5 Sheets-Sheet 5 Filed Feb. 25, 1960 FIG. 7

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United States Patent 3,655,025 SWNG FMS 0R FLIIPERS Luigi Ferraro and Antonio Cressi, also known as Egitlio (Zressi both of iiazza Beata Frassinetti I'i/A, Genoa- Quinto, Italy Filed Feb. 25, 1960, Ser. No. 11,048 Claims priority, application Italy Apr. 20, 1959 9 Claims. ((11. 9-309) The present invention concerns swimming fins or flippers for wearing on the feet by swimmers.

All previously known swimming fins or flippers are defective in their operation due to their mechanical structure. In fact they have a zone which, during one of the swinging movements of the legs, exerts on the water a passive action in the sense that, as a minimum disadvantage it absorbs energy without producing work, but, in the majority of cases, it exerts an undesirable action contrary to the direction of motion.

If, in fact, one refers to the particular swinging movement of the legs during swimming, it is apparent that one phase is totally active, while the contrary phase is only partially active, active meaning the action intended to give impulse to the swimming itself, that is to say, to cause the advance of the swimmer.

The invention will be described further, by way of example in reference to the accompanying drawings, in which:

FIG. 1 is a view of a swimmer swimming head downwards;

FIG. 2 is a theoretical view of the upward movement phase of the legs;

FIG. 3 is a theoretical view of the downward phase of movement of the legs;

FIG. 4 is a plan view of a fin constructed in accordance with the present invention;

FIG. 5 is a cross section taken on the line 5-5 of FIG. 4;

FIG. 6 is a theoretical view of the downward movement of the legs fitted with the fin of the present invention with a relative diagram of forces;

FIG. 7 is a plan view of a fin constructed in accordance with the present invention and provided with only two passages; and

FIG. 8 is a section taken on the line S-8 of FIG. 7 showing in dotted lines the position of the aperture of the valve.

In practice, if a swimmer is considered to be swimming face downwards (FIG. 1) it is apparent that the phase of the upward movement of the legs is positive (FIG. 2) because the whole surface of the fin acts on the water in the direction A so as to cause a reaction or thrust equal and contrary in the direction B.

If the vector B comprises the components C and D, C is the active component assisting motion and D has no influence and can therefore be omitted.

In the opposite phase, that is to say, in the phase of downward movement of the leg, the condition (FIG. 1) is different inasmuch as in these circumstances, there are three separate zone portions in the fin, the first or active zone portion I resulting in the total active output, the second or inactive zone portion II in no active output and the third or impeding zone portion III giving an output impeding the direction of swimming. Its operation may be analysed as follows:

The first zone produces an action on the water in the direction E and receives a thrust in the direction F, the vector of which can be analysed into the component C without any eflect on the motion and the component H which assists motion.

The second zone is neutral in that the action and reice actions are equivalent and constitute a condition of equilibrium.

The third zone which exerts on the water an action in direction I causes a reaction in direction L, the vector of which can be analysed into the component M which does not influence the movement and the component N which is contrary to the direction of movement.

The case may be substantially summarised as follows:

One of the zones in which the actual structure of the fins may be theoretically sub-divided, exerts a negative action or such contrary to the direction of motion which the present invention has the object of eliminating.

According to the present invention, this zone is provided with apertures or passages controlled on the supporting surface of the fin by displaceable flaps as valves adapted to perform two active operations at the same time. In fact they permit the escape of water, thereby reducing the pressure on the zone which happens to be contrary to the direction of swimming, thus overcoming the resistance of the water.

Due to the particular construction, flexibility and position of the valves, this discharge is automatically utilised by said valves which thus also assume the function of propelling members, increasing the value of the forward thrust, given, in this phase by the single useful Zone of the fins.

In other words the above described construction achieves a positive value on a zone of a fin which, in the present state of prior art, has a negative value.

Referring to the FIGS. 4 to 6 of the drawings, the fin body has apertures K extending therethrough from its upper surface 3, the rear or lower ends of these apertures being covered by a displaceable valve R formed by a flap constituted by a sheet of rubber or the like connected on one of its smaller sides Z, namely that nearest the heel, to the lower face of the fin body. Also extending from the upper surface 3 is at least one rib T between adjacent apertures K for guiding the flow of water through the apertures.

In the embodiment illustrated in FIGS. 7 and 8, the construction is generally similar to that of the embodiment of FIGS. 4, 5 and 6, but only two apertures 4 are used. The openings 4 are controlled by a flap 5 connected to the fin body by means of a transverse hinge 7.

As far as the operation of the above fin is concerned, it will be apparent from the theory set forth above, in view of the fact that in the upward movement of the leg, the valves close the discharge openings of the water thus creating an entire supporting surface on the water with a total active output of the entire lower surface of the fin, while, in the contrary action, that is to say, when the water pressure offers resistance on the negative zone of the fin, the valves open permitting the discharge of the water and thereby reducing the pressure. Furthermore, the valves, due to their particular shape, arrangement and flexibility, act as functional propelling members, exploiting the discharge current which is caused by the opening of the valves, in :a similar manner on the active zone of the fins. In fact, in the said phase in which a part of the surface of the fin would be negative, the valves R (FIG. 6) act on the water with the value P through which it it derives a reaction Q which is made up of the vector V which does not influence the motion and the vector S which assists the motion of translation.

Naturally, the construction of the fin in accordance with the invention may assume in practice variations in outline and the apertures may assume any direction, arrangement, shape and size and the valves may be of any nature, shape and size and provided with a connection to the fin to render them displaceable in a suitable manner without departing from the scope of the invention.

What we claim is:

1. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion attached to said securing portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with at least One aperture therethrough; and closure means mounted on said flexible web portion adjacent said aperture movable between aperture closing and aperture opening positions and constructed in such manner that said closure means will automatically move fr m aperture closing into aperture opening position when water is forced through said aperture in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

2. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion secured to said securing portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with at least one aperture therethrough; and flap means hingedly mounted on said flexible web portion adjacent said aperture movable between aperture closing and aperture opening positions and constructed in such manner that said closure means will automatically move from aperture closing into aperture opening position when water is forced through said aperture in a direction from said upper face to said bottom sole face thereof and automatically cl se when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

3. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion secured to said securing portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with at least one aperture therethrough; and flap means hingedly mounted on the bottom sole face of said flexible web portion adjacent said aperture movable between aperture closing and aperture opening position and constructed in such manner that said closure means will automatically move from aperture closing into aperture opening position when water is forced through said aperture in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

4. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion attached to said securing portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with a plurality of apertures therethrough; and a flap mounted on said flexible web portion adjacent said apertures movable between aperture closing and aperture opening positions and constructed in such manner that said flap will automatically move from aperture closing into aperture opening position when water is forced through said apertures in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

5. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion attached to said securing portion and adapted .to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with a plurality of apertures adjacent each other therethrough and having atleast one rib between said adjacent apertures for guiding the flow of water therethrough; and a flap mounted on said flexible web port on adjacent said apertures movable between aperture closing and aperture opening positions and constructed in such manner that said flap will automatically move from aperture closing into aperture opening position when water is forced through said aperture in a direction from said upper face to said bottom sole face thereof and automatically close When water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

6. A swim flipper comprising, in combination, a securing portion adapted to be attached to the foot of the swimmer; a flexible web portion integral with said securing portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion being formed with at least one aperture therethrough adjacent said securing portion; and closure means mounted on said flexible web portion adjacent said aperture movable between aperture closing and aperture opening positions and constructed in such manner that said closure means will automatically move from aperture closing into aperture opening position when water is forced through saidaperture in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

7. A swim flipper comprising, in combination, a foot portion adapted to be secured to at least a part of the foot of the swimmer; a flexible web portion integral with said foot portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion including an impeding zone portion immediately adjacent the foot portion, an active zone portion at the furthermost extension of said web portion, and an inactive zone portion intermediate said impeding and active zone portions, said impeding zone portion being formed with at least one aperture therethrough; and flap means hingedly supported on the bottom sole face of said impeding Zone portion adjacent said aperture movable between aperture closing and aperture opening positions and constructed in such manner that said flap means will automatically move from aperture closing into aperture opening position when water is forced through said aperture in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

8. A swim flipper comprising, in combination, a foot portion adapted to be secured to at least a part of the foot of the swimmer; a flexible web portion integral with said foot portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion including an impeding zone portion immediately adjacent the foot portion, an active zone portion at the furthermost extension of said web portion, and an inactive zone portion intermediate said peding and active zone portions, said impeding zone portion being formed with a plurality of adjacent apertures therethrough and having a rib between each pair of adjacent apertures for guiding the flow of water therethrough; and flap means hingedly supported on the bottom sole face of said impeding zone portion adjacent said aperture movable between aperture closing and aperture opening positions and constructed in such manner that said flap means will automatically move from aperture closing into aperture opening position when water is forced through said aperture in a di-' rection from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

9. A swim flipper comprising, in combination, a foot portion adapted to be secured to at least a part of the foot of the swimmer; a flexible web portion integral with said foot portion and adapted to extend forwardly of the foot forming an extension thereof and having a bottom sole face and an upper face, said flexible web portion including an impeding zone portion immediately adjacent the foot portion, an active zone portion at the furthermost extension of said web portion, and an inactive zone portion intermediate said impeding and active zone portions, said impeding zone portion being formed with a plurality of adjacent apertures therethrough; and a single flap hingedly supported on the bottom sole face of said impeding zone portion adjacent said apertures movable be tween aperture closing and aperture opening positions and constructed in such manner that said flap will automatically move from aperture closing into aperture opening position when water is forced through said apertures in a direction from said upper face to said bottom sole face thereof and automatically close when water is forced against said bottom sole face of said flexible web portion in a direction toward said upper face thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,889,563 Lamb June 9, 1959 FOREIGN PATENTS 444,567 Italy Jan. 25, 1949 

